I don't think it's premature to start judging the iPhone 5. Here is what we know:

1. It looks pretty much the same as an iPhone 4 but it is longer. The caseback has a slightly different material/color/texture. Most people, including myself, would cover the back up for the entire life of the phone with a case anyway.

2. The technical specs look about the same as the Galaxy S3.

3. The OS will run faster, but it is essentially the same OS that Apple has been using since Day 1.

I do think the iPhone looks good, and the fact that the back is made out of metal/aluminum (?) and not plastic. It also retains its value very well so when you need to sell it or upgrade, you'll get back a lot of money. I don't know how a Galaxy would fare in that department.

I'm in the same boat. I'm finally upgrading my dumbphone five years after everyone else. I own a MacBook Pro. Does that mean I should definitely get the iPhone?

If you've never had a smartphone I think the iPhone would be a good choice. I also have a Macbook Pro but that would not affect my decision at all. Your phone's interaction with your computer would be the same (iTunes) if you have a PC or Mac.

Every time I pick up and use a non-Apple smart phone the first thing that pops through my head is that it feels like a cheap plastic toy. I'll switch over when Android is acceptable as an OS and the phones actually feel like products that are worth what they cost.